Exodus 39:20-22

Complete Jewish Bible

²⁰ Also they made two gold rings and attached them low on the front part of the vest’s shoulder-pieces, near the join, above the vest’s decorated belt. ²¹ Then they bound the breastplate by its rings to the rings of the vest with a blue cord, so that it could be on the vest’s decorated belt, and so that the breastplate would not swing loose from the vest — as Adonai had ordered Moshe.

(RY: vi, LY: iii) ²² He made the robe for the ritual vest; it was woven entirely of blue,